# test 01 (Si O2)
## d-spacing (A)   angle_to_x (deg)
# 1  1  1    2.2689
2.2671   0.15
# 2  0  2    1.3894
1.3878   35.08
# 2  3  2    0.9531
0.9624  -11.61

# angle((1,1,1),(2,3,2))
# 11.421753658962279
# angle((1,1,1),(2,0,2))
# 35.264389682754654
# angle((2,3,2),(2,0,2))
# 46.686143341716949

# zone axis : [-1,  0,  1]